Molecular Biology MCQs | BIO302 MCQs | Set 1
Molecular Biology MCQs | BIO302 MCQs | Set 1
MCQs (Multiple Choice Questions)
1) The hydrophilic backbones of alternating deoxyribose and phosphate groups are inside the double helix, facing the surrounding water?
a) True
b) False
c) False in certain cases
d) a and c
Correct Answer:
The correct answer is 'b'.
Explanation:
The statement is false (option b) because in the double helix structure of DNA, the hydrophilic (water-attracting) backbones, which consist of alternating deoxyribose sugar and phosphate groups, are located on the outside of the double helix. The hydrophilic backbones face the surrounding water, while the hydrophobic (water-repelling) nitrogenous bases are protected and oriented toward the interior of the helix. This arrangement helps shield the nitrogenous bases from the surrounding aqueous environment, which is important for maintaining the stability and integrity of the DNA molecule.
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2) Chromosomes are made up of _____.
a) Protein and DNA
b) DNA and RNA
c) RNA and protein
d) a & c
Correct Answer:
The correct answer is 'a'.
Explanation:
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3) Chromosome theory of inheritance by Thomas Hunt Morgan was presented in____
b) 1912
d) 1910
Correct Answer:
The correct answer is 'd'.
Explanation:
Thomas Hunt Morgan presented his chromosome theory of inheritance in 1910.
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4) Nucleotide consists of ____ major molecules
a) 2
b) 3
c) 4
d) 5
Correct Answer:
The correct answer is 'b'.
Explanation:
A nucleotide consists of three major molecules:
- A phosphate group (1 molecule)
- A five-carbon sugar (such as deoxyribose or ribose) (1 molecule)
- A nitrogenous base (either adenine, thymine, guanine, cytosine, or uracil) (1 molecule)
These three components make up the basic building block of nucleic acids like DNA and RNA. The combination of these three major molecules forms the structure of a nucleotide, and they play a fundamental role in the storage and transmission of genetic information and various cellular processes.
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5) How many amino acids are there in one compelete tern of DNA______.
a) 6.3
b) 3.6
c) 36
d) 4.6
Correct Answer:
The correct answer is 'c'.
Explanation:
One complete turn of DNA contains 10 base pairs. Each base pair encodes for one amino acid. Therefore, one complete turn of DNA encodes for 10 amino acids.
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6) Nucleosome fold to form the _______ fiber.
a) 20 nm
b) 30 nm
c) 40 nm
d) 50 nm
Correct Answer:
The correct answer is 'b'.
Explanation:
The 30 nm fiber represents a more condensed and organized form of chromatin in which nucleosomes are stacked and interact with each other, creating a higher level of compaction. This folding of nucleosomes into the 30 nm fiber helps package DNA efficiently within the cell nucleus while still allowing access to the genetic information when needed.
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7) On which media, cells are preferred to be grown?
a) N14
b) Pb
c) Cs
d) Ra
Correct Answer:
The correct answer is 'a'.
Explanation:
N14 is a nutrient medium that is commonly used to grow cells. It is a complex medium that contains all of the nutrients that cells need to grow and divide. N14 is typically used to grow cultured cells, such as fibroblasts, epithelial cells, and stem cells.
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8) DNA polymerase has ________ domains
a) 3
b) 4
c) 5
d) 6
Correct Answer:
The correct answer is 'a'.
Explanation:
All DNA polymerases contain three domains:
- Fingers domain: Interacts with the dNTP and the paired template base.
- Palm domain: Catalyzes the reaction of the transfer of the phosphoryl group.
- Thumb domain: Positions the dNTP at the active site and stabilizes the newly formed phosphodiester bond.
Some DNA polymerases may also have additional domains, such as an exonuclease domain for proofreading and mismatch repair. However, all DNA polymerases have the three essential domains listed above.
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9) An E.Coli chromosome is estimated to have about_______super-coiled loops
a) 500
b) 400
c) 300
d) 200
Correct Answer:
The correct answer is 'b'.
Explanation:
The E. coli chromosome is organized into loops known as "supercoiled domains." These loops help in the compaction of the genetic material within the bacterial cell.
The estimated number of supercoiled loops in an E. coli chromosome is approximately 400.
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10) Separation of DNA is accomplished by __________.
a) Type I topoisomerase
b) Type I topoisomerase
c) Type I topoisomerase
d) DNA polymease
Correct Answer:
The correct answer is 'b'.
Explanation:
Type II topoisomerases are enzymes that can cut both strands of a DNA molecule and then religate them. This allows them to change the topology of DNA, which can be useful for a variety of processes, such as DNA replication and recombination.
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